Vehicle sound simulation systems can generate sounds that correspond to an estimation of the current state or performance of a combustion engine. Typical vehicle sound simulation systems can approximate the current state or performance of a combustion engine by monitoring various aspects of the combustion engine during operation. In this regard, a typical vehicle sound simulation system may have one or more electrical sensors that are specifically designed to measure one or more combustion engine operation parameters. Examples of such combustion engine operation parameters include manifold pressure, exhaust pressure, or engine tachometer readings. As the development of alternative vehicle propulsion systems or power plants increases, traditional combustion engine operation parameters may no longer serve as viable means to approximate the current state or performance of the propulsion system or power plant. For example, manifold pressure sensors may not be able to approximate the current state or performance of an electric engine or hybrid electric engine.
Most vehicle sound simulation systems attempt to closely coordinate the generated sounds in accordance with the matched state of the engine. For example, in a traditional vehicle sound simulation system, if the driver presses against the throttle pedal, the combustion engine is assumed to be in an accelerating state and a corresponding sound should be generated contemporaneously. Likewise, in a traditional vehicle sound simulation system, if the driver releases the throttle pedal, the combustion engine is assumed to be in a decelerating state and corresponding sounds should be generated contemporaneously. As previously described, however, because vehicle sound simulation system systems are typically coupled to a motor vehicle's tachometer, or other electrical sensors, time delays created between the determination of state of the engine from the tachometer (or other sensor) and the generated simulated sound from the vehicle sound simulation system can be present. The frequency and length of such delays can impact the effectiveness of the vehicle sound simulation system.